This is a pilot study intended to exaine blood levels of INH, RIF, and PZA, and blood levels in combination drug Rifamate (INH and RIF). The intention is to evaluate the difference of absorption, if any, of the drugs. In this study we plan to evaluate whether or not absorption values between the two types of pharmacokinetics differ at least 10%, evaluate the overall absorption rates of the two different drug combinations, and determine if the blood levels achieved at the various timepoints are consistent with those cited by the manufacturers. Patients without HIV infetion who are AFB smear positive or culture positive and are presently on standard therapy will be eligible. All enrolled patients must be 18 years of age or older and have no history of renal, hepatic, and bone marrow disease. Patients will be hospitalized in negative air pressure rooms for approximately 23 hrs. The patients will be NPO approximately 8 hours before drug administration. Drug therapy will be administered per standard for Rifamate (combination INH and Rifampin) or INH and Rifampin given separately. Timed blood draws will be performed at 30 min, 1 hr, 2 hr, 3 hr, 4 hr and 6 hr. The patient will then be discharged.